/**
 * @license
 * Copyright (c) 2019 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

/**
 * The top-level interface of a custom-elements.json file.
 *
 * Because custom elements are JavaScript classes, describing a custom element
 * may require describing arbitrary JavaScript concepts like modules, classes,
 * functions, etc. So custom-elements.json documents are capable of documenting
 * the elements in a package, as well as those JavaScript concepts.
 *
 * The modules described in a package should be the public entrypoints that
 * other packages may import from. Multiple modules may export the same object
 * via re-exports, but in most cases a package should document the single
 * canonical export that should be used.
 */
export interface Package {
  /**
   * The version of the custom-elements.json schema used in this file.
   */
  schemaVersion: string;

  /**
   * The Markdown to use for the main readme of this package.
   *
   * This can be used to override the readme used by Github or npm if that
   * file contains information irrelevant to custom element catalogs and
   * documentation viewers.
   */
  readme?: string;

  /**
   * An array of the modules this package contains.
   */
  modules: Array<Module>;
}

// This type may expand in the future to include JSON, CSS, or HTML
// modules.
type Module = JavaScriptModule;

export interface JavaScriptModule {
  kind: 'javascript-module';

  path: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description of the module.
   */
  description?: string;

  /**
   * The declarations of a module.
   *
   * For documentation purposes, all declarations that are reachable from
   * exports should be described here. Ie, functions and objects that may be
   * properties of exported objects, or passed as arguments to functions.
   */
  declarations: Array<Declaration>;

  /**
   * The exports of a module. This includes JavaScript exports and
   * custom element definitions.
   */
  exports?: Array<Export>;
}

export type Export = JavaScriptExport | CustomElementExport;

export interface JavaScriptExport {
  kind: 'js';

  /**
   * The name of the exported symbol.
   *
   * JavaScript has a number of ways to export objects which determine the
   * correct name to use.
   *
   * - Default exports must use the name "default".
   * - Named exports use the name that is exported. If the export is renamed
   *   with the "as" clause, use the exported name.
   * - Aggregating exports (`* from`) should use the name `*`
   */
  name: string;

  /**
   * A reference to the exported declaration.
   *
   * In the case of aggregating exports, the reference's `module` field must be
   * defined and the `name` field must be `"*"`.
   */
  declaration: Reference;
}

/**
 * A global custom element defintion, ie the result of a
 * `customElements.define()` call.
 *
 * This is represented as an export because a definition makes the element
 * available outside of the module it's defined it.
 */
export interface CustomElementExport {
  kind: 'custom-element-definition';

  /**
   * The tag name of the custom element.
   */
  name: string;

  /**
   * A reference to the class or other declaration that implements the
   * custom element.
   */
  declaration: Reference;
}

export type Declaration =
  | ClassDeclaration
  | FunctionDeclaration
  | MixinDeclaration
  | VariableDeclaration
  | CustomElement;

/**
 * A reference to an export of a module.
 *
 * All references are required to be publically accessible, so the canonical
 * representation of a reference is the export it's available from.
 *
 * Referrences to global symbols like `Array`, `HTMLElement`, or `Event`
 *
 */
export interface Reference {
  name: string;
  package?: string;
  module?: string;
}

/**
 * Description of a custom element class.
 *
 * Custom elements are JavaScript classes, so this extends from
 * `ClassDeclaration` and adds custom-element-specific features like
 * attributes, events, and slots.
 *
 * Note that `tagName` in this interface is optional. Tag names are not
 * neccessarily part of a custom element class, but belong to the definition
 * (often called the "registration") or the `customElements.define()` call.
 *
 * Because classes and tag anmes can only be registered once, there's a
 * one-to-one relationship between classes and tag names. For ease of use,
 * we allow the tag name here.
 *
 * Some packages define and register custom elements in separate modules. In
 * these cases one `Module` should contain the `CustomElement` without a
 * tagName, and another `Module` should contain the
 * `CustomElement`.
 */
export interface CustomElement extends ClassDeclaration {
  /**
   * An optional tag name that should be specified if this is a
   * self-registering element.
   *
   * Self-registering elements must also include a CustomElementExport
   * in the module's exports.
   */
  tagName?: string;

  /**
   * The attributes that this element is known to understand.
   */
  attributes?: Attribute[];

  /**
   * The events that this element fires.
   */
  events?: Event[];

  /**
   * The shadow dom content slots that this element accepts.
   */
  slots?: Slot[];

  parts?: CssPart[];

  cssProperties?: CssCustomProperty[];

  demos?: Demo[];
}

export interface Attribute {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;

  /**
   * The type that the attribute will be serialized/deserialized as.
   */
  type?: Type;

  inheritedFrom?: Reference;

  /**
   * The default value of the attribute, if any.
   *
   * As attributes are always strings, this is the actual value, not a human
   * readable description.
   */
  defaultValue?: string;

  /**
   * The name of the field this attribute is associated with, if any.
   */
  fieldName?: string;
}

export interface Event {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;

  inheritedFrom?: Reference;

  /**
   * The type of the event object that's fired.
   */
  type: Type;
}

export interface Slot {
  /**
   * The slot name, or the empty string for an unnamed slot.
   */
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;
}

/**
 * The description of a CSS Part
 */
export interface CssPart {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;
}

export interface CssCustomProperty {
  /**
   * The name of the property, including leading `--`.
   */
  name: string;

  defaultValue?: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;
}

export interface Type {
  /**
   * The full string representation of the type, in whatever type syntax is
   * used, such as JSDoc, Closure, or TypeScript.
   */
  type: string;

  /**
   * An array of references to the types in the type string.
   *
   * These references have optional indices into the type string so that tools
   * can understand the references in the type string independently of the type
   * system and syntax. For example, a documentation viewer could display the
   * type `Array<FooElement | BarElement>` with cross-references to `FooElement`
   * and `BarElement` without understanding arrays, generics, or union types.
   */
  references?: TypeReference[];
}

/**
 * A reference that is associated with a type string and optionally a range
 * within the string.
 *
 * Start and end must both be present or not present. If they're present, they
 * are indices into the associated type string. If they are missing, the entire
 * type string is the symbol referenced and the name should match the type
 * string.
 */
export interface TypeReference extends Reference {
  start?: number;
  end?: number;
}

/**
 * The common interface of classes and mixins.
 */
export interface ClassLike {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description of the class.
   */
  description?: string;
  superclass?: Reference;
  mixins?: Array<Reference>;
  members?: Array<ClassMember>;
}

export interface ClassDeclaration extends ClassLike {
  kind: 'class';
}

export type ClassMember = ClassField | ClassMethod;

/**
 * The common interface of variables, class fields, and function
 * parameters.
 */
export interface PropertyLike {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description of the field.
   */
  description?: string;

  type?: Type;

  default?: string;
}

export interface ClassField extends PropertyLike {
  kind: 'field';
  static?: boolean;
  privacy?: Privacy;
  inheritedFrom?: Reference;
}

export interface ClassMethod extends FunctionLike {
  kind: 'method';
  static?: boolean;
  privacy?: Privacy;
  inheritedFrom?: Reference;
}

/**
 *
 */
export interface MixinDeclaration extends ClassLike, FunctionLike {
  kind: 'mixin';
}

export interface VariableDeclaration extends PropertyLike {
  kind: 'variable';
}

export interface FunctionDeclaration extends FunctionLike {
  kind: 'function';
}

export interface Parameter extends PropertyLike {
  /**
   * Whether the parameter is optional. Undefined implies non-optional.
   */
  optional?: boolean;
}

export interface FunctionLike {
  name: string;

  /**
   * A markdown summary suitable for display in a listing.
   */
  summary?: string;

  /**
   * A markdown description.
   */
  description?: string;

  parameters?: Parameter[];

  return?: {
    type?: Type;
    description?: string;
  };
}

export type Privacy = 'public' | 'private' | 'protected';

export interface Demo {
  /**
   * A markdown description of the demo.
   */
  description?: string;

  /**
   * Relative URL of the demo if it's published with the package. Absolute URL
   * if it's hosted.
   */
  url: string;
}